Title : Deepening knowledge about vitamin D: new ways to measure it, new ways to supplement it, new ways to understand it
Goal: To compare the levels of vitamin D3 in the blood and tears of healthy young adults practicing indoor and outdoor physical activities and to compare them among themselves and with people with eye diseases, and to evaluate the effects of supplementation with vitamin D3 eye drops.
Method: 36 volunteers (19a 27years), without ocular diseases, were separated into two groups: indoor activities (sun exposure <3h / week) and outdoor (> 7h / week). 22 people with keratoconus, ocular disease that causes an ectasia of the cornea, were examined as well. Vitamin D3 levels in blood (3 ml of venous blood) and tear (Schirmer strips) were evaluated in all participants of this study. Both the tear and the blood passed through the electrochemiluminescence method, to evaluate the levels of the metabolite 25 (OH) vitamin D3. After this, vitamin D3 eye drops were used to evaluate possible changes at these levels.
Result: The mean plasma vitamin D3 level of the indoor group was 25.01 ng / ml, while the mean plasma vitamin D3 level of the outdoor group was 35.55 ng / ml (p <0.05), and was 22,25ng/ml in keratoconus group. In all 36 healthy participants, vitamin D3 levels in the tear were higher than 100 ng / ml (the maximum limit of the system used), well above the plasma levels in the two groups of participants (p<0,01). In the keratoconus group the tear mean level was 66,59 ng/m (p<0,0001)l. In 6 of these randomly chosen healthy subjects, the prepared vitamin D3 eye drops were used, in which each drop contained 5000 IU, and 1 drop was instilled in each eye 2 times a day for 3 weeks to evaluate serum levels. An average increase in the plasma level of 25.18%, ranging from 9.2 to 42.8%.
Conclusion: Lacrimal levels of vitamin D3 were significantly higher than plasma levels in both internal and external physical activities (p <0.01). The eye drops were effective and increased serum D3 levels by 25.18%, with only 3 weeks of use, proving the usefulness of the conjunctival pathway for vitamin D3 absorption. Vitamin D3 levels were much lower in people with keratoconus than healthy people, especially in tears. These results are unprecedented in the world literature.